Without it, your body would quickly begin to decay as bacteria, viruses, fungi, parasites, and diseases invade the body and eat away at your cells. Even an immune system functioning at partly reduced effectiveness leaves the body vulnerable to these invading substances. The key to maintaining a healthy immune system is to know what weakens it and what strengthens it.
How the immune system functions
The job of your immune system is to defend the body against foreign or dangerous substances that attack it. These substances can come from outside the body or from unhealthy cells that may develop inside the body. Your body has several lines of defense against invaders: your skin; the membranes lining the respiratory, digestive, urinary, and reproductive tracts; and sticky mucus and fluids in your eyes, nose, and mouth.
The second and most important line of defense is your immune system; a complex system of white blood cells that must work synergistically together to be effective. There are 16 different types of white blood cells, and some of the most important are macrophages, Natural Killer (NK) cells, T cells, and B cells.
Suppose someone sneezes near you…
Harmful germs and agents rush into your body. The largest white cells in your body, macrophages, meet these invaders and like little Pacmen, begin swallowing and digesting them.
Then, your fiercest and most important white blood cells, NK cells, join the attack. Your NK cells identify and kill any harmful cells. They inject the invader cells with cytotoxic granules and the invader cells quickly explode. When a full out attack is needed, your NK cells sound the alarm to coordinate and bring in reinforcements, T cells and B cells.
NK cells are vitally important to your front line of defense because they not only sound the alarm for a coordinated effort in your immune system but they are natural born killers—no training necessary.
How T Cells Work
Unlike NK cells, T cells do have to go through a “training program” before they can graduate and become killers of invaders. T cells are formed in the bone marrow. They then have to “go to school” in the thymus gland, which is behind your breastbone.
During training, they mature and learn the difference between good cells that they’re supposed to leave alone and bad invading cells that they’re supposed to kill off. They aren’t allowed to leave the classroom (the thymus) until they get this right.
But sometimes T cells skip class (scientists aren’t sure why) and they can’t distinguish good from bad cells. When this happens, T cells may attack your own body and destroy good cells. This is called an autoimmune response. Allergies, lupus, and rheumatoid arthritis are examples of the immune system attacking healthy cells.
How B Cells Work
Your bone marrow also produces B cells. B cells are white blood cells that produce antibodies. Each antibody is a specialist. And because each antibody attaches itself to a specific type of invader, this action signals all types of white blood cells to join the attack against invaders.
As you can see, white blood cells are critical to a healthy immune system and are a measure of good health. For men, a strong immune system has a normal white cell count of 5,000 to 10,000 microliters. For non-pregnant women, about 4,500 to 11,000. So what weakens and what strengthens the immune system?
Four Reasons the Immune System Weakens
Reason 1: Constant daily stress—bills, the economy, traffic, holidays, family concerns, world events, etc.—is one of the biggest contributing factors to a weak immune system. During stress, the body releases cortisol, which suppresses the immune system. In addition, a person fighting the physical and emotional stress of unhealthy cells that have developed in the body has an even more difficult challenge.
Reason 2: Poor sleep weakens the immune system. One study found that even one night of poor sleep slashed Natural Killer cell activity by almost 33%.
Reason 3: Aging weakens immunity. Researchers know that B cells and T cells slow down and malfunction with age. With these malfunctions, white blood cells will sometimes attack good cells instead of bad ones.
Reason 4: Elevated blood sugar levels and weight gain can lead to decreased immunity. Eating too much sugar and fat can suppress the function of immune system cells.
Six Ways to Boost Your Immune System
Booster 1: Frequent hand washing (15-20 seconds at each washing) is one of the best ways to prevent the spread of infection and illness, according to the Centers for Disease Control. This is because 80% of all infectious diseases are passed by human contact.
Booster 2: Laugh with friends and family. Scientists know that having a close social network helps to increase immune function. Laughter has been shown to boost NK cells, T cells, and B cells. Depression on the other hand, can negatively affect the immune system because it inhibits the fighting ability of your T cells.
Booster 3: Exercise. Studies show that moderate, daily exercise—like 30 minutes of walking—raises your white blood cell count. Yoga also helps to reduce stress. Stress is a major factor that weakens the immune system.
Booster 4: Listen to your favorite music. Studies have shown that music boosts IgA, antibodies that fight invaders.
Booster 5: Eat brightly colored foods rich in antioxidants and flavanoids. Some of the best ones are: cranberries, strawberries, citrus, broccoli, red wine, red grapes, and grape juice. Tomatoes, apples, onions, and garlic contain the powerful flavanoid quercetin.
Booster 6: Mushrooms, used in traditional Japanese healing, can be beneficial. Look for a mushroom extract that helps to activate the immune system’s Natural Killer cells, your body’s line of defense.